CCTV footage from buses parked at Oxford Bus Company's depot in Cowley is to be analysed by police trying to catch a would-be robber and his accomplice.

A female cashier at the site in Watlington Road managed to break free after a man dressed in black motorcycle leathers and a helmet threatened her as she left the office at about 7.50am on Monday.

It is thought the man may have been carrying a gun or weapon.

Company director and general manager Louisa Weeks said: "We're relieved that our colleague wasn't seriously hurt in the incident - even though she forced the would-be robbers to leave empty-handed.

"Although she was quite shocked by what happened, she is back at work and is determined to get on with her job as normal.

"Security is extremely tight at our headquarters and the whole of the area is covered by CCTV cameras.

"It was a Bank Holiday and there were more buses than normal still on site waiting to go into service."

As the 39-year-old Oxford woman, who has not been named, escaped, the would-be robber left empty-handed on the back of a large motorcycle driven by another man, who was also wearing dark motorcycle leathers and a bike helmet.

Police are trying to track down the drivers of two vehicles who may have seen the motorbike.

The first was an old-style yellow Renault Megane, which was seen overtaking the motorbike in Watlington Road.

The second was a white van with ladders on the roof, which slowed down to allow the motorcycle to turn into Watlington Road.

Anyone with information is asked to call Dc Steve Clarke on 08458 505505 or Crimestoppers on 0800 555111.